Here are the two telescopes I use for deep space astrophotography. The imaging telescope is an 8" f/4.9 newtonian reflector. Mounted on top of the imaging telescope is the guide scope, an 80mm f/11 refractor.

The telescope is relatively inexpensive, but well suited for deep sky astrophotography due to the relatively large aperture (eight inches) and fast optics (f/4.9). The primary optical element is an 8" concave parabolic mirror with a focal length of 1000 mm (about 39 inches). The primary mirror is located at the bottom of the tube, and the focused image is reflected back towards the front of the tube, where it is intercepted by a small, flat elliptical mirror placed in the center of the tube at a 45 degree angle. This secondary mirror reflects the image 90 degrees towards the side of the tube, where an eyepiece can be used to examine the image visually, after focusing it by adjusting the eyepiece position up or down with the focuser, seen projecting from the side of the tube near the top. The small telescope seen in this photo near the focuser is a "finder scope", used to locate and center objects before attempting to view them through an eyepiece.

Mounted on top of the imaging telescope, the guide scope is used to keep the mount tracking the photographic subject perfectly. Attached to the eyepiece-end of the guide scope in this photo is a small CCD camera. When the imaging telescope is pointed at the photographic subject, the guide scope is focused on a nearby star and images of that star are captured by the CCD camera and sent to a laptop PC. Software on the PC tracks the guide star and sends commands to the mount, via a serial cable, to adjust the position of the mount in order to keep the guide star from drifting. Thus, imperfections in the mount's tracking are eliminated.